lis3: add three new laptop models

Separate the 6710 and 6715, and set the right axis information for the
6715.
Reported-by: Isaac702 <isaac702@gmail.com>

Add the 6930.
Reported-by: Christian Weidle <slateroni@gmail.com>

Add the 2710.
Reported-by: Pavel Herrmann <morpheus.ibis@gmail.com>

Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>